Texas Jack might have been a character with a reputation in the community. He could have been a frontiersman, someone who was among the first to explore and settle in certain areas of Texas. He might have been involved in building relationships with Native Americans or in establishing trade routes. There are many possibilities.
In the Jack the Ripper story, Jack the Ripper was a very infamous figure. He preyed on women in a poor area of London. There have been many suspects proposed over time, from local butchers to members of the upper class trying to cover up some sordid secrets. But no one has been definitively proven to be him.
Jack Walker in this fanfiction is likely the main character. He's someone who has his own story within the Pokemon - themed world. Maybe he's a unique trainer with special abilities or a backstory that sets him apart from other trainers in the fan - made story.
One possible scenario in this fanfiction could be that Syndrome, still bitter about his defeat by the Incredibles, targets Jack - Jack as a way to get revenge. He might see Jack - Jack's multiple powers as a valuable asset or a threat that needs to be neutralized. Syndrome could use his high - tech gadgets to abduct Jack - Jack while the family is distracted.
One great Samurai Jack female Jack fanfiction could be 'The Adventures of Female Jack'. It might show her facing different challenges in the same post - apocalyptic world as the original Jack. Another could be 'Female Jack: A New Path' which could explore her forging her own unique destiny, different from the male Jack's journey.
It's not straightforward to determine. Maybe the author intended it to be based on truth, or it could just be a product of pure imagination. Without more context, it's tough to tell.